CN111033949B

CN111033949B - Spoke type motor, motor for vehicle, unmanned aerial vehicle, and electric booster

Info

Publication number: CN111033949B
Application number: CN201880052987.8A
Authority: CN
Inventors: 绵引正伦; 上田智哉
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2017-09-27
Filing date: 2018-09-04
Publication date: 2022-04-19
Anticipated expiration: 2038-09-04
Also published as: DE112018005518T5; CN111033949A; WO2019065119A1; JP2021007275A

Abstract

One aspect of the present invention provides a spoke motor including a stator and a rotor relatively rotatable with respect to the stator about a central axis line extending in a vertical direction, the rotor including: a shaft disposed along the central axis; a rotor core having a plurality of core members arranged apart from each other in a circumferential direction on a radially outer side of the shaft; and a plurality of permanent magnets that are arranged alternately with the core members in the circumferential direction on the outside in the radial direction of the shaft, the plurality of permanent magnets exciting the core members, the core members including: a scattering prevention section that covers a part of the outer side in the radial direction of the permanent magnet; and a notch portion disposed toward the center line from a position that is farther from the center line in the circumferential direction of the permanent magnet covered by the scattering prevention portion than an end portion of the scattering prevention portion in the radial direction.

Description

Spoke type motor, motor for vehicle, unmanned aerial vehicle, and electric booster

Technical Field

The invention relates to a spoke motor, a motor for a vehicle, an unmanned aerial vehicle, and an electric booster.

Background

In a spoke type motor, a structure for preventing the permanent magnets from scattering due to a centrifugal force generated when the rotor rotates is required. As a scattering prevention structure of the permanent magnet, a structure is also known in which the permanent magnet and the rotor core are resin-molded to prevent scattering of the permanent magnet.

A structure is known in which the shape of the rotor core is designed to prevent the permanent magnets from scattering. For example, japanese patent application laid-open No. 8-009599 discloses a structure for preventing permanent magnets from scattering by a protrusion provided on a rotor core. For example, japanese patent application laid-open No. 2000-152534 discloses a structure in which a permanent magnet is inserted into a rotor core to prevent the permanent magnet from scattering.

Prior patent literature

Patent document

Patent document 1: japanese laid-open patent publication No. 8-009599

Patent document 2: japanese patent laid-open No. 2000-152534

Disclosure of Invention

Problems to be solved by the invention

However, in the structure in which the scattering of the permanent magnets is prevented by resin molding, there is a possibility that the strength is insufficient due to the rotation speed of the rotor. As described in japanese patent application laid-open nos. 8-009599 and 2000-152534, in a structure in which a part of a rotor core covers the radial outer side of a permanent magnet, the magnetic flux distribution is disturbed by the part of the rotor core covering the radial outer side of the permanent magnet. When the magnetic flux distribution is disturbed, the vibration may be increased by pulsation of cogging torque or the like. When the magnetic flux distribution is disturbed, vibration having a high electrical angle order may be increased.

One aspect of the present invention has been made in consideration of the above problems, and an object thereof is to provide a spoke motor, a vehicle motor including the spoke motor, an unmanned aerial vehicle, and an electric booster, which can maintain the flying prevention strength of a permanent magnet and can reduce vibration.

Means for solving the problems

According to a first aspect of the present invention, there is provided a spoke type motor including: a stator; and a rotor that is rotatable relative to the stator about a central axis extending in a vertical direction, the rotor including: a shaft disposed along the central axis; a rotor core having a plurality of core members arranged apart from each other in a circumferential direction on a radially outer side of the shaft; and a plurality of permanent magnets that are arranged alternately with the core members in a circumferential direction on an outer side in a radial direction of the shaft, the plurality of permanent magnets exciting the core members, the core members including: a scattering prevention section that covers a part of the outer side of the diameter of the permanent magnet; and a notch portion disposed toward the center line from a position that is farther from the center line in the circumferential direction of the permanent magnet covered by the scattering prevention portion than an end portion of the scattering prevention portion in the radial direction.

According to a second aspect of the present invention, there is provided a vehicle motor including the spoke motor of the first aspect as a motor for driving a dual clutch transmission.

According to a third aspect of the present invention, there is provided an unmanned aerial vehicle including the spoke motor of the first aspect.

According to a fourth aspect of the present invention, there is provided an electric booster including the spoke motor of the first aspect.

Effects of the invention

According to one embodiment of the present invention, the scattering prevention strength of the permanent magnet can be maintained, and the vibration can be reduced.

Drawings

Fig. 1 is a sectional view showing a motor of embodiment 1.

Fig. 2 is a view showing the rotor of embodiment 1, and is an IV-IV cross-sectional view shown in fig. 1.

Fig. 3 is a graph showing a relationship between an electrical angle and a radial magnetic flux density of a tooth in a stator.

Fig. 4 is a graph showing a relationship between the number of electrical angles and the radial magnetic flux density of the tooth portion.

Fig. 5 is a graph showing a relationship between the number of electrical angles (4 times) and the radial electromagnetic force.

Fig. 6 is a graph showing a relationship between the number of electrical angles (10 times) and the radial electromagnetic force.

Fig. 7 is a partial sectional view showing the rotor of embodiment 2.

Fig. 8 is a view of the rotor according to embodiment 2 as viewed from the radially outer side.

Fig. 9 is a perspective view showing an example of the unmanned aerial vehicle 2000.

Fig. 10 is a front view of the electric bicycle 3000.

Detailed Description

A spoke type motor according to an embodiment of the present invention will be described below with reference to the drawings. The scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical idea of the present invention. In the following drawings, in order to facilitate understanding of each structure, the actual structure may be different from each structure in scale, number, and the like.

In the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional rectangular coordinate system. In the XYZ coordinate system, the Z-axis direction is a direction parallel to the axial direction of the central axis J shown in fig. 1. The X-axis direction is a direction perpendicular to the Z-axis direction and is the left-right direction in fig. 1. The Y-axis direction is set to a direction perpendicular to both the X-axis direction and the Z-axis direction. The circumferential direction around the central axis J is defined as the θ Z direction. Regarding the θ Z direction, a clockwise direction when viewed from the-Z side toward the + Z side is defined as a positive direction, and a counterclockwise direction when viewed from the-Z side toward the + Z side is defined as a negative direction.

In the following description, the direction (Z-axis direction) in which the central axis J extends is referred to as the vertical direction. The positive side (+ Z side) in the Z-axis direction is referred to as "upper side (axially upper side)", and the negative side (-Z side) in the Z-axis direction is referred to as "lower side". The vertical direction, the upper side, and the lower side are names used for illustration only, and do not limit the actual positional relationship or direction. Also, unless otherwise specified, a direction parallel to the central axis J (Z-axis direction) is simply referred to as "axial direction", a radial direction centering on the central axis J is simply referred to as "radial direction", and a circumferential direction centering on the central axis J (θ Z direction), that is, a direction of an axis around the central axis J is simply referred to as "circumferential direction".

Further, a side that advances in the positive direction in the θ Z direction (+ θ Z side, one side in the circumferential direction) is referred to as a "driving side", and a side that advances in the negative direction in the θ Z direction (- θ Z side, the other side in the circumferential direction) is referred to as a "reverse driving side". The drive side and the reverse drive side are names used for explanation only, and do not limit the actual drive direction.

In the present specification, the term "extend in the axial direction" includes not only a case where the extend is strictly in the axial direction (Z-axis direction), but also a case where the extend is in a direction inclined by less than 45 ° with respect to the axial direction. In the present specification, the term "extend in the radial direction" includes a case where the extension is strictly in the radial direction, that is, in the direction perpendicular to the axial direction (Z-axis direction), and a case where the extension is in a direction inclined by less than 45 ° with respect to the radial direction.

[ spoke type Motor ]

< embodiment 1 >

Fig. 1 is a sectional view showing a spoke type motor 10 (hereinafter, simply referred to as a motor 10) of embodiment 1. As shown in fig. 1, the motor 10 of the present embodiment includes a housing 20, a rotor 30 having a shaft 31, a stator 40, a lower bearing (bearing) 51, an upper bearing (bearing) 52, and a bus bar unit 60.

The housing 20 houses the rotor 30, the stator 40, the lower bearing 51, the upper bearing 52, and the bus bar unit 60. The housing 20 has a lower housing 21 and an upper housing 22. The lower housing 21 has a cylindrical shape opened at both sides (± Z side) in the axial direction. The upper housing 22 is fixed to an upper (+ Z side) end of the lower housing 21. The upper case 22 covers the upper sides of the rotor 30 and the stator 40.

The stator 40 is held inside the lower housing 21. The stator 40 is located radially outward of the rotor 30. The stator 40 includes a core back 41, teeth 42, a coil 43, and a bobbin 44. The core back 41 has a cylindrical shape concentric with the central axis J, for example. The outer side surface of the core back 41 is fixed to the inner side surface of the lower housing 21.

The tooth 42 extends from the inner side surface of the core back 41 toward the shaft 31. Although not shown in fig. 1, a plurality of teeth 42 are provided, and the plurality of teeth 42 are arranged at equal intervals in the circumferential direction. A bobbin 44 is attached to each tooth 42. The coil 43 is wound around each tooth 42 via a bobbin 44.

The bus bar unit 60 is located on the upper side (+ Z side) of the stator 40. The bus bar unit 60 has a connector portion 62. An external power supply not shown is connected to the connector 62. The bus bar unit 60 has a wiring member electrically connected to the coil 43 of the stator 40. One end of the wiring member is exposed to the outside of the motor 10 through the connector portion 62. Thereby, power is supplied from an external power supply to the coil 43 through the wiring member. The bus bar unit 60 has a bearing holding portion 61.

The lower bearing 51 and the upper bearing 52 support the shaft 31. The lower bearing 51 is located on the lower side (on the-Z side) than the stator 40. The lower bearing 51 is held by the lower housing 21. The upper bearing 52 is located at the upper side (+ Z side) than the stator 40. The upper bearing 52 is held by a bearing holding portion 61 of the bus bar unit 60.

The rotor 30 has a shaft 31 and a rotor core 32. The shaft 31 is centered on a central axis J extending in the vertical direction (Z-axis direction). The rotor core 32 is located radially outward of the shaft 31. In the present embodiment, the rotor core 32 is fixed to the outer peripheral surface of the shaft 31. In the present embodiment, the rotor 30 rotates counterclockwise about the center axis J, i.e., from the reverse drive side (- θ Z side) to the drive side (+ θ Z side) when viewed from the upper side (+ Z side), for example.

Fig. 2 is an enlarged partial view of section IV-IV in fig. 1.

As shown in fig. 2, the rotor core 32 shown in fig. 1 has a plurality of permanent magnets 33 and a plurality of core members 34. That is, the rotor 30 includes a plurality of permanent magnets 33 and a plurality of core members 34. The permanent magnet 33 excites the core member portion 34. The permanent magnets 33 are arranged alternately with the core members 34 in the circumferential direction.

The permanent magnet 33 is inserted into a magnet insertion hole 38 described later. The permanent magnet 33 includes

permanent magnets

33A and 33B. The permanent magnets 33A and the permanent magnets 33B are alternately arranged in the circumferential direction. In the following description, the permanent magnet 33 will be described as being represented by the permanent magnet 33A and the permanent magnet 33B.

The

permanent magnets

33A and 33B have two magnetic poles arranged in the circumferential direction. The permanent magnet 33A has, for example, an N pole on the driving side (+ θ Z side) and an S pole on the reverse driving side (- θ Z side). The permanent magnet 33B has, for example, an S pole on the driving side (+ θ Z side) and an N pole on the reverse driving side (- θ Z side). Thereby, the magnetic poles of the

permanent magnets

33A, 33B adjacent in the circumferential direction are opposed to each other with the same polarity in the circumferential direction.

The permanent magnet 33A and the permanent magnet 33B have the same configuration except for the difference in the arrangement of the magnetic poles in the circumferential direction. Therefore, in the following description, only the permanent magnet 33A will be representatively described in some cases.

The permanent magnet 33A extends in the radial direction. The permanent magnet 33A has a rectangular shape in cross section perpendicular to the axial direction (Z-axis direction), for example. In the present specification, the rectangular shape includes a substantially rectangular shape. The substantially rectangular shape includes a state in which corners of the rectangle are chamfered, for example.

In the present embodiment, for example, five permanent magnets 33A are provided. The permanent magnets 33B are provided with five, for example.

The core member 34 has an inner core portion 34I and an outer core portion 34O. The inner core portion 34I is located radially outward of the shaft 31 and radially inward of the

permanent magnets

33A, 33B. The inner core portion 34I has a radially inner support portion 35 that supports the

permanent magnets

33A, 33B. The core member 34 has a cavity 37 around the support portion 35. The cavity portion 37 is a magnetic shielding portion that suppresses leakage of magnetic flux in the support portion 35.

The outer core portion 34O has

core pieces

34N, 34S. The

core members

34N, 34S are arranged apart from each other in the circumferential direction on the radially outer side of the shaft 31. The core members 34N and the core members 34S are alternately arranged in the circumferential direction. The core member portion 34N is located between the N pole of the permanent magnet 33A and the N pole of the permanent magnet 33B. Thereby, the core member portion 34N is excited to the N pole. The core member portion 34S is located between the south pole of the permanent magnet 33A and the south pole of the permanent magnet 33B. Thereby, the core member portion 34S is excited to the S pole.

The magnet insertion hole 38 is disposed between the

core members

34N and 34S adjacent to each other in the circumferential direction. The magnet insertion hole 38 is a hole into which the permanent magnet 33A is inserted. The magnet insertion hole portions 38 are adjacent to the

core members

34N, 34S adjacent in the circumferential direction. The core member 34N has an opposing surface 36N circumferentially opposing the N-pole of the

permanent magnets

33A, 33B. The core member portion 34S has an opposing surface 36S that circumferentially opposes the south pole of the

permanent magnets

33A, 33B. That is, the opposing surface 36N and the opposing surface 36S are part of the inner surface of the magnet insertion hole 38.

The core member 34N includes a scattering prevention portion 1N and a notch portion 2N. The scattering prevention portion 1N covers a part of the radial outer side of the

permanent magnets

33A, 33B. The scattering prevention portion 1N is provided over the entire portion of the rotor core 32 in the axial direction. The scattering prevention section 1N is disposed radially outward of the

permanent magnets

33A and 33B. The scattering prevention section 1N has an end 1Na facing the center line C side in the circumferential direction of the

permanent magnets

33A and 33B covered by the scattering prevention section 1N. The distance in the circumferential direction from the facing surface 36N to the end portion 1Na is shorter than the distance in the circumferential direction from the facing surface 36N to the center line C. The distance in the circumferential direction from the center line C to the end 1Na is shorter than the distance in the circumferential direction from the center line C to the N-electrode-side end face of the

permanent magnet

33A, 33B.

The core member portion 34S has a scattering prevention portion 1S and a notch portion 2S. The scattering prevention portion 1S covers a part of the radial outer side of the

permanent magnets

33A, 33B. The scattering prevention portion 1S is provided over the entire portion of the rotor core 32 in the axial direction. The scattering prevention section 1S is disposed radially outward of the

permanent magnets

33A and 33B. The scattering prevention section 1S has an end portion 1Sa facing the circumferential center line C side of the

permanent magnets

33A and 33B covered by the scattering prevention section 1S. The distance in the circumferential direction from the opposing surface 36S to the end portion 1Sa is shorter than the distance in the circumferential direction from the opposing surface 36N to the center line C. The distance in the circumferential direction from the center line C to the end 1Sa is shorter than the distance in the circumferential direction from the center line C to the S-pole side end faces of the

permanent magnets

33A, 33B.

The

anti-scattering portions

1N, 1S support the

permanent magnets

33A, 33B radially outward when the rotor 30 rotates about the center axis J. The

permanent magnets

33A and 33B are supported radially outward by the

scattering prevention portions

1N and 1S, and thus the

permanent magnets

33A and 33B can be prevented from scattering radially outward by a centrifugal force generated by rotation of the rotor 30. The

scattering prevention portions

1N and 1S are provided over the entire axial portion of the rotor core 32, and thus the

permanent magnets

33A and 33B can be more reliably prevented from scattering radially outward due to the centrifugal force.

The notch 2N is disposed radially outward of the scattering prevention portion 1N. The notch portion 2N is provided over the entire portion of the rotor core 32 in the axial direction. The notch 2N is disposed toward the center line C from a position that is a longer circumferential distance from the center line C than the end 1Na of the scattering prevention portion 1N. The circumferential distance between the end 2Nb of the notch portion 2N on the side closer to the center line C in the circumferential direction and the center line C is the same as the distance to the end 1Na of the scattering prevention portion 1N. The end 2Nb of the notch 2N is a spatial position, and thus shows a virtual position. The end 2Nb of the notch 2N overlaps the

permanent magnets

33A and 33B in the radial direction.

The circumferential distance between the circumferential end 2Na of the notch 2N on the side away from the center line C and the center line C is longer than the distance to the N-electrode-side end face of the

permanent magnets

33A and 33B. That is, the notch portion 2N is provided between the following two end portions: an end 2Nb at the same circumferential position as the circumferential position of the end 1Na of the scattering prevention section 1N; and an end portion 2Na having a longer circumferential distance from the center line C than the distance to the N-pole-side end surface of the

permanent magnets

33A, 33B. An end portion 2Na of the notch portion 2N on the side away from the center line C does not overlap with the

permanent magnets

33A and 33B in the radial direction. The radially inner position of the notch portion 2N is preferably close to the central axis J within a range where the scattering prevention portion 1N can prevent the

permanent magnets

33A, 33B from scattering radially outward.

The notch 2S is disposed radially outward of the scattering prevention portion 1S. The notch 2S is provided over the entire portion of the rotor core 32 in the axial direction. The notch 2S is disposed toward the center line C from a position that is a longer circumferential distance from the center line C than the end 1Sa of the scattering prevention portion 1S. The circumferential distance from the center line C of the circumferential end portion 2Sb on the side closer to the center line C in the notched portion 2S is the same as the distance to the end portion 1Sa of the scattering prevention portion 1S. The end portion 2Sb of the notch portion 2S is a spatial position, and thus shows a virtual position. The end 2Sb of the notch 2S overlaps the

permanent magnets

33A and 33B in the radial direction.

The circumferential distance between the circumferential end portion 2Sa of the cutout portion 2S on the side away from the center line C and the center line C is longer than the distance to the S-electrode-side end surface of the

permanent magnet

33A, 33B. That is, the notched portion 2S is provided between two end portions: an end portion 2Sb at the same circumferential position as the end portion 1Sa of the scattering prevention portion 1S; and an end portion 2Sa having a longer circumferential distance from the center line C than the S-pole side end surfaces of the

permanent magnets

33A and 33B. An end portion 2Sa of the cutout portion 2S on the side away from the center line C does not overlap with the

permanent magnets

33A, 33B in the radial direction. In order to reduce disturbance of the magnetic flux distribution, the position on the radially inner side of the notch portion 2S is preferably close to the central axis J within a range where the scattering prevention portion 1S can prevent the

permanent magnets

33A, 33B from scattering toward the radially outer side.

The core member portion 34N and the core member portion 34S have the same configuration except that the arrangement of the magnetic poles in the circumferential direction excited by the

permanent magnets

33A and 33B is different. Therefore, in the following description, only the core member portion 34N will be representatively described in some cases.

By setting the circumferential position of the end portion 2Na of the notch portion 2N in the core member portion 34N according to the number of pole pairs and the number of electrical angles of the

permanent magnets

33A, 33B, it is possible to provide a magnetic flux density in opposite phase to the radial magnetic flux density of the number of electrical angles and cancel out.

When the number of pole pairs of the

permanent magnets

33A and 33B is P and the number of electrical angles is N, an angle Δ θ between the end portion 2Na of the notch portion 2N centered on the central axis J and the center line C is expressed by the following formula (1).

Δθ＝(π/P)×(1/N)…(1)

The effective range in which the above-described opposite-phase magnetic flux density can be offset by the position of the end portion 2Na is 0.5 times or more and 1.5 times or less larger than Δ θ obtained by the above-described formula (1). That is, the following expression (2) may be satisfied in order to provide a flux density in opposite phase to the radial flux density of the electrical angle order N and cancel the flux density.

0.5×(π/P)×(1/N)≤Δθ≤1.5×(π/P)×(1/N)…(2)

Fig. 3 is a graph showing a relationship between an electrical angle (deg) and a radial magnetic flux density (T) of the teeth 42 in the stator 40. For example, in the electrical angle in fig. 3, the circumferential position of the center line C is 150 ° and 330 °, and the circumferential center position of the core member portion 34N is 60 °. A graph G1 indicated by a broken line in fig. 3 shows a relationship between the electrical angle (deg) and the radial magnetic flux density (T) of the tooth portion 42 in the case where the notched portion 2N is not provided in the core member portion 34N. A graph G2 shown by a solid line in fig. 3 shows a relationship between the electrical angle (deg) and the radial magnetic flux density (T) of the tooth portion 42 in the case where the notched portion 2N is provided in the core member portion 34N.

When the scattering prevention portion 1N of the core member portion 34N covers a part of the outer side in the radial direction of the

permanent magnets

33A and 33B and the notch portion 2N is not provided, the magnetic flux distribution is disturbed as shown in fig. 3, and becomes a graph G1 deviating from a sine wave. When the scattering prevention portion 1N of the core member portion 34N covers a part of the outside in the radial direction of the

permanent magnets

33A and 33B and the notch portion 2N is provided, a graph G2 in which the radial magnetic flux density has a sinusoidal waveform is shown. Graph G2 is a sinusoidal waveform with a radial flux density that varies between a maximum value T1 and a minimum value T2, while graph G1 is a wave form that deviates from the sinusoidal waveform with a radial flux density that varies between a maximum value T3(T3< T1) and a minimum value T4(T4> T2).

Fig. 4 is a graph showing a relationship between the number of electrical angles and the radial magnetic flux density (T) of the tooth portion 42. The left graph indicated by a non-hatched (hashing) among the numbers of electrical angles in fig. 4 shows the relationship between the number of electrical angles and the radial magnetic flux density in the case where the core member portion 34N is not provided with the notch portion 2N. In the right graph of the number of electrical angles in fig. 4, the number of electrical angles in the case where the notched portion 2N is provided in the core member portion 34N and the radial magnetic flux density are shown in a hatched manner.

In the motor 10, a spatial harmonic component of the magnetic flux distribution may be one of the causes of the higher-order vibration component. In the spoke type motor 10, as shown in fig. 4, particularly the 3 rd order component and the 9 th order component adversely affect the high order vibration.

By setting the position of the end portion 2Na in the notch portion 2N according to equations (1) and (2), the radial electromagnetic force acting on the number of electrical angles (N +1) of the tooth portion 42 can be reduced. By reducing the radial electromagnetic force acting on the tooth portions 42, the radial vibration of the motor 10 can be reduced.

For example, the amplitude of the radial magnetic flux density was confirmed for each of the core member portion 34N in which the position of the end portion 2Na was set according to the electrical angles of the orders of expression (1), expression (2), and 3 and the core member portion 34N in which the position of the end portion 2Na was set according to the electrical angles of the orders of expression (1), expression (2), and 9. As shown in fig. 4, the amplitude of the radial magnetic flux density is the same as that of the structure without the notch portion 2N with respect to the electrical angle of 9 times, but the amplitude of the radial magnetic flux density can be reduced from the maximum value T11 to the maximum value T12, approximately to 17%, with respect to the electrical angle of 3 times, as compared with the structure without the notch portion 2N.

Fig. 5 is a graph showing a relationship between the number of electrical angles (4 times) and the radial electromagnetic force. In fig. 5, the left graph shown without hatching shows the relationship between the number of electrical angles and the radial electromagnetic force in the case where the core member portion 34N is not provided with the notch portion 2N. In fig. 5, the right graph shown in a hatched manner shows the relationship between the number of electrical angles (4 times) and the radial electromagnetic force in the case where the notched portion 2N is provided in the core member portion 34N.

As shown in fig. 5, the radial electromagnetic force in the case where the position of the end portion 2Na is set in the core member portion 34N according to the electrical angle of 3 times can be reduced to about 12% as compared with the electromagnetic force in the case where the notch portion 2N is not provided in the core member portion 34N.

Fig. 6 is a graph showing a relationship between the number of electrical angles (10 times) and the radial electromagnetic force. In fig. 6, the left graph shown without hatching shows the relationship between the number of electrical angles and the radial electromagnetic force in the case where the core member portion 34N is not provided with the notch portion 2N. In fig. 6, the right graph shown in a hatched manner shows the relationship between the number of electrical angles (10 times) and the radial electromagnetic force in the case where the notched portion 2N is provided in the core member portion 34N.

As shown in fig. 6, the radial electromagnetic force in the case where the position of the end portion 2Na is set in the core member portion 34N according to the electric angle of 9 times can be reduced to about 74% as compared with the electromagnetic force in the case where the notch portion 2N is not provided in the core member portion 34N.

< embodiment 2 >

The embodiment 2 differs from the embodiment 1 in that: the circumferential position of the end portion 2Na of the notch portion 2N on the side away from the center position C and the circumferential position of the end portion 2Sa of the notch portion 2S on the side away from the center position C. Note that the same components as those in embodiment 1 may be omitted from description by appropriately designating the same reference numerals.

Fig. 7 is a partial sectional view showing the rotor 30 of the present embodiment. As shown in fig. 7, the end 2Na of the notch 2N on the side away from the center position C overlaps the

permanent magnets

33A and 33B in the radial direction. An end portion 2Sa of the cutout portion 2S on the side away from the center position C overlaps the

permanent magnets

33A and 33B in the radial direction.

The magnetic flux in the present embodiment is directed from the region overlapping the

permanent magnets

33A and 33B in the radial direction toward the tooth portion 42 on the side of the core member portion 34N farther from the center position C than the end portion 2 Na. The magnetic flux in the present embodiment is directed from the tooth portion 42 toward the region overlapping the

permanent magnets

33A and 33B in the radial direction on the side of the core member portion 34S farther from the center position C than the end portion 2 Sa. Therefore, even when the

notch portions

2N and 2S are provided in the

core members

34N and 34S, the area through which the magnetic flux flows increases, and thus the flow of the magnetic flux can be suppressed from being excessively concentrated.

< embodiment 3 >

Embodiment 3 differs from embodiment 1 in that the

scattering prevention portions

1N, 1S are provided at a part of the rotor core 32 in the axial direction. Note that the same components as those in embodiment 1 may be omitted from description by appropriately designating the same reference numerals.

Fig. 8 is a view of the

permanent magnets

33A, 33B and the

core members

34N, 34S as viewed from the radially outer side. Each of the core members 34N has a plurality of core pieces LN stacked in the axial direction. The core pieces LNa disposed at both ends in the axial direction among the plurality of core pieces LN have the scattering prevention portions 1N covering a part of the outside in the radial direction of the

permanent magnets

33A, 33B. The notch 2N is provided in both the core piece LNa having the scattering prevention portion 1N and the core piece LN not having the scattering prevention portion 1N. That is, the notch 2N is provided in all the core pieces LN.

The core members 34S each have a plurality of core pieces LS stacked in the axial direction. The core pieces LSa arranged at both ends in the axial direction among the plurality of core pieces LS have the scattering prevention portions 1S covering a part of the outside in the radial direction of the

permanent magnets

33A, 33B. The notch 2S is provided in both the core segment LSa having the scattering prevention portion 1S and the core segment LS not having the scattering prevention portion 1S. That is, the notch 2S is provided in all the core pieces LS.

In the rotor 30 of the present embodiment, the

permanent magnets

33A and 33B are prevented from scattering radially outward by centrifugal force by the

scattering prevention portions

1N and 1S, and only the core segments LSa cover a part of the radially outward sides of the

permanent magnets

33A and 33B, so that the rotor 30 can be reduced in weight. In the rotor 30 of the present embodiment, the notch portions 2N are provided in all the core segments LN, and the notch portions 2S are provided in all the core segments LS, so that the influence of the axial magnetic flux leakage can be reduced.

In the motor 10 described in the above embodiment, the

permanent magnets

33A and 33B and the

core members

34N and 34S may be molded by a resin material. When the

permanent magnets

33A, 33B and the

core members

34N, 34S are molded with a resin material, a part of the

permanent magnets

33A, 33B on the outer side in the radial direction can be covered with the resin material. The resin material covering a part of the

permanent magnets

33A, 33B on the radial outer side serves as a 2 nd scattering prevention portion for preventing the

permanent magnets

33A, 33B from scattering on the radial outer side due to a centrifugal force. By preventing the

permanent magnets

33A and 33B from scattering by using the

scattering prevention portions

1N and 1S and the resin material together, scattering of the

permanent magnets

33A and 33B can be more reliably prevented. By preventing the

permanent magnets

33A and 33B from scattering by using the

scattering prevention portions

1N and 1S and the resin material in combination, the positions radially inside the

notch portions

2N and 2S can be made closer to the central axis J. By positioning the radially inner sides of the

notches

2N and 2S closer to the central axis J, disturbance of the magnetic flux distribution can be reduced.

The motor 10 to which the present invention is applied is not particularly limited in application, and can be used for gear selection of a Transmission such as a Dual Clutch Transmission (DCT) mounted in a vehicle or for driving a Clutch, for example. By using the motor 10 to which the present invention is applied, vibration of the motor for a vehicle can be reduced.

The motor 10 to which the present invention is applied is used in, for example, an unmanned aerial vehicle. Fig. 9 is a perspective view showing an example of the unmanned aerial vehicle 2000. The unmanned aerial vehicle 2000 has a main body 2001, a rotary blade portion 2002, an image pickup device 500, and a motor 10. The motor 10 drives the rotary blade 2002 to rotate. Since the unmanned aerial vehicle 2000 has the motor 10, it is possible to fly with low vibration. The unmanned aerial vehicle 2000 can perform high-precision imaging while flying with low vibration.

The motor 10 to which the present invention is applied is used in an electric booster, for example. Fig. 10 is a front view of an electric bicycle 3000 as an example of an electric booster. The electric power-assisted bicycle 3000 is a bicycle that assists a person with a motor.

The electric bicycle 3000 includes a microprocessor 200 as a signal processing device, the motor 10, and a battery 400, in addition to components of a general bicycle. Examples of components of a typical bicycle include a handlebar 100, a frame 11, a front wheel 12, a rear wheel 13, a seat 14, a chain 15, pedals 16, and a crank 17. The rear wheel 13 is mechanically connected to a motor 30 by means of a chain 15. The rear wheel 13 is rotated by a manual torque applied through the pedals 16 and a motor torque applied through the motor 10. Thereby, the electric power-assisted bicycle 1 is driven.

Since the electric bicycle 3000 includes the motor 10, it is driven with low vibration, and riding comfort is improved.

Although the preferred embodiments according to the present invention have been described above with reference to the drawings, it is needless to say that the present invention is not limited to the examples according to the present invention. The shapes, combinations, and the like of the respective components shown in the above examples are examples, and various modifications can be made in accordance with design requirements and the like within a scope not departing from the gist of the present invention.

The present application claims priority to japanese patent application No. 2017-186010, which is a japanese patent application applied on 27/9/2017, and cites the entire contents of the description in the japanese patent application.

Description of the reference symbols

1N, 1S: an anti-scattering section; 2N, 2S: a notch portion; 10: a spoke motor (motor); 30: a rotor; 31: a shaft; 32: a rotor core; 33A, 33B: a permanent magnet; 34. 34N, 34S: a core member portion; 40: a stator; 2000: an unmanned aerial vehicle; 3000: electric power-assisted bicycles (electric power-assisted devices); c: a centerline; j: a central axis.

Claims

1. A spoke motor includes:

a stator; and

a rotor that is relatively rotatable with respect to the stator around a central axis extending in a vertical direction,

the rotor is provided with:

a shaft disposed along the central axis;

a rotor core having a plurality of core members arranged apart from each other in a circumferential direction on a radially outer side of the shaft; and

a plurality of permanent magnets that are arranged alternately with the core members in a circumferential direction on an outer side in a radial direction of the shaft, the plurality of permanent magnets exciting the core members,

the core member includes:

a scattering prevention section that covers a part of the outer side in the radial direction of the permanent magnet; and

a notch portion disposed toward the center line from a position that is farther from the center line in the circumferential direction of the permanent magnet covered by the scattering prevention portion than an end portion of the scattering prevention portion is, in a position radially outward of the scattering prevention portion,

when an angle between the center line of the permanent magnet in the circumferential direction and an end portion of the notch portion on a side away from the center line in the circumferential direction is Δ θ, a pole pair number of the permanent magnet is P, and the number of electrical angles is N, the following relationships are satisfied:

0.5×(π/P)×(1/N)≤Δθ≤1.5×(π/P)×(1/N)。

2. the spoke motor of claim 1,

an end portion of the cutout portion on a side closer to the center line in the circumferential direction overlaps the permanent magnet in a radial direction at a position radially outward of the permanent magnet.

3. The spoke motor of claim 1,

an end portion of the cutout portion on a side away from the center line in the circumferential direction overlaps the permanent magnet in a radial direction at a position radially outward of the permanent magnet.

4. The spoke motor of claim 1,

the scattering prevention portion is provided to the entire portion of the rotor core in the axial direction.

5. The spoke motor of claim 1,

the scattering prevention portion is provided at a part of the rotor core in an axial direction.

6. The spoke motor of claim 1,

the spoke motor includes a second scattering prevention portion that covers a part of the permanent magnet on the outer side in the radial direction with a resin material.

7. A motor for a vehicle, comprising the spoke type motor according to any one of claims 1 to 6 as a motor for driving a dual clutch transmission.

8. An unmanned aerial vehicle provided with the spoke motor according to any one of claims 1 to 6.

9. An electric booster comprising the spoke motor according to any one of claims 1 to 6.